International Patent Application WO20100015614 of 4 Aug. 2009 describes a method for forming webs of transversely extensible fibrous material, in particular paper webs. According to this disclosure, a web of pliable fibrous material having a certain water content is made to adhere to an elastic surface temporarily and locally stretched in a direction perpendicular to the web advancement direction and maintained adhering to said elastic surface at least until this has substantially resumed its original configuration.